Tier 2b — Access Control

Plaintext

Information in normal, readable form

Ciphertext

Encrypted, unreadable form

Encryption algorithm

The mathematical formula used to encrypt or decrypt

Encryption key

The password (input to the algorithm) used to encrypt/decrypt

Symmetric encryption

SAME key encrypts and decrypts — FAST, key management is hard

Asymmetric encryption

Public/private key pair — slower, scales better with many users

Symmetric vs asymmetric

Symmetric is FAST; asymmetric SCALES better with many users

AES

Advanced Encryption Standard — example of SYMMETRIC encryption

RSA

Rivest-Shamir-Adleman — example of ASYMMETRIC encryption

TLS

Transport Layer Security — modern encryption for data in transit (successor to SSL)

HTTPS

HTTP with TLS encryption (port 443) — secures data in transit

Data at rest

Stored data — protect with full-disk encryption, file encryption

Data in transit

Data moving over a network — protect with TLS, HTTPS, VPN

Data in use

Data in active memory/being processed — hardest to protect

Hash function

One-way function — variable-length input to fixed-length output

Message digest

The fixed-length output produced by a hash function

Hash characteristic - one-way

Cannot be reversed

Hash characteristic - fixed length

Output is fixed-length regardless of input size

Hash characteristic - collision resistance

No two inputs should produce the same output

MD5

128-bit hash — NO LONGER secure

SHA-1

160-bit hash — NO LONGER secure

SHA-2

Hash family producing 224/256/384/512-bit outputs — currently secure

SHA-3

Newer hash (2015), user-selected length — very secure

RIPEMD

Non-government hash alternative — 160-bit version used in Bitcoin

Data lifecycle stage 1 - Create

New data is created or existing data modified

Data lifecycle stage 2 - Store

Data is placed in a storage repository

Data lifecycle stage 3 - Use

Data is read or processed

Data lifecycle stage 4 - Share

Data is shared with vendors, partners, or authorized parties

Data lifecycle stage 5 - Archive

Data no longer actively used moved to long-term storage

Data lifecycle stage 6 - Destroy

Data is disposed of using a secure method

Top Secret

Highest government/military classification

Secret

Second-highest government/military classification

Confidential

Third-tier government/military classification

Unclassified

Lowest government/military classification

Highly Sensitive

Highest business classification

Sensitive

Second-highest business classification

Internal

Third-tier business classification

Public

Lowest business classification

Clearing

Data destruction — overwrites data to frustrate casual recovery (lowest severity)

Purging

Data destruction — advanced techniques to frustrate laboratory analysis (medium)

Destroying

Data destruction — complete obliteration (shredding, melting, burning)

Degaussing

Strong magnetic field destroys magnetic media (doesn't work on SSDs)

Remanence

Residual data left on storage after deletion — why wiping is needed

Cross-cut shredding

Required method for sensitive paper destruction

Ingress monitoring

Watching data coming INTO the network

Egress monitoring

Watching data going OUT — detects exfiltration

Accountability

Identity attribution — identifies who caused an event

Traceability

Uncovers the chain of related events

Auditability

Clear documentation of events that can be reviewed

Event

Any observable occurrence in a system or network

Incident

An event that violates security policy or threatens CIA

Breach

Confirmed incident where unauthorized party actually accessed data

Zero day

A vulnerability unknown to defenders — no patch exists yet

APT

Advanced Persistent Threat — sophisticated, long-running attacker (often nation-state)

Exploit

A specific technique used to take advantage of a vulnerability

Intrusion

Unauthorized access to a system

RFC

Request for Change — formal proposal for a change to be reviewed

Rollback

Reverting to a previous known-good state if a change fails

Patch management

Process for testing, approving, deploying software patches

Hardening

Reducing attack surface by disabling unneeded services

CDN

Content Delivery Network — geographically distributed servers for fast content

MTTR

Mean Time To Repair — average time to fix a failed component

MTBF

Mean Time Between Failures — expected time between system failures

Wet pipe fire suppression

Pipes full of water — risk of leak damaging electronics

Dry pipe fire suppression

Pipes empty until alarm — slight delay, no incidental water damage

Chemical fire suppression

Deprives fires of oxygen — dangerous to people in the room